Negative Stain Electron Microscopy

The negative stain technique is typically used to quickly evaluate sample quality as a first step in single-particle EM projects. Purified, isolated particles of a protein or protein complex are deposited onto the carbon support film of an EM grid. The sample is then coated with a heavy metal salt stain such as uranyl-formate. This allows visualisation of negatively stained particles in the EM. Negative stain samples can be screened in one of our Tecnai TEMs. The resolution of negative stain EM can reach ca. 20 Å, which is sufficient to determine the homogeneity, purity, concentration and integrity of a sample.